Creep Behavior of Rotating Ferritic Steel Disk Using the Θ Projection Concept

In this article, time-dependent creep stress redistribution behavior of a rotating ferritic steel disk is studied by means of a long-term creep constitutive model. The material long-term creep properties are defined by the Θ projection concept based on the experimental results previously published in the literature. Loading is composed of an inertia body force due to rotation and a constant temperature filed throughout the disk. The equilibrium equation, stress-strain and straindisplacement relations are employed to obtain the constitutive differential equation. Considering creep strains the differential equation becomes nonhomogenous and time-dependent. To obtain history of radial, circumferential and effective stresses a numerical procedure using Taylor series and Prandtle-Reuss relations is employed. It has been found that considerable redistribution for stresses occurs during the life of the disk. The stresses are increasing with time which must be considered for the safe design of ferritic steel disk. The results are compared with a new published work considering Al-SiC composite disk to show the significant effect of material creep properties on time-dependent behavior of rotating disk.

Keywords:

Ferritic Steel , time-dependent creep , stress redistribution , rotating disk , Θ projection concept